From: Martin Schiller <ms@dev.tdt.de>
Date: Thu, 26 Nov 2020 06:35:55 +0000 (+0100)
Subject: net/lapb: fix t1 timer handling for LAPB_STATE_0
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=62480b992ba3fb1d7260b11293aed9d6557831c7;p=linux.git

net/lapb: fix t1 timer handling for LAPB_STATE_0

1. DTE interface changes immediately to LAPB_STATE_1 and start sending
   SABM(E).

2. DCE interface sends N2-times DM and changes to LAPB_STATE_1
   afterwards if there is no response in the meantime.

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/lapb/lapb_timer.c b/net/lapb/lapb_timer.c
index 8f5b17001a076..baa247fe4ed05 100644
--- a/net/lapb/lapb_timer.c
+++ b/net/lapb/lapb_timer.c
@@ -85,11 +85,18 @@ static void lapb_t1timer_expiry(struct timer_list *t)
 	switch (lapb->state) {
 
 		/*
-		 *	If we are a DCE, keep going DM .. DM .. DM
+		 *	If we are a DCE, send DM up to N2 times, then switch to
+		 *	STATE_1 and send SABM(E).
 		 */
 		case LAPB_STATE_0:
-			if (lapb->mode & LAPB_DCE)
+			if (lapb->mode & LAPB_DCE &&
+			    lapb->n2count != lapb->n2) {
+				lapb->n2count++;
 				lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
+			} else {
+				lapb->state = LAPB_STATE_1;
+				lapb_establish_data_link(lapb);
+			}
 			break;
 
 		/*